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Insertions into the set are slow when we try to add many elements.
For 800k elements I get:
time nft -f pipapo_800k
real 19m34.849s
user 0m2.390s
sys 19m12.828s
perf stats:
--95.39%--nft_pipapo_insert
|--76.60%--pipapo_insert
| --76.37%--pipapo_resize
| |--72.87%--memcpy_orig
| |--1.88%--__free_pages_ok
| | --0.89%--free_tail_page_prepare
| --1.38%--kvmalloc_node
..
--18.56%--pipapo_get.isra.0
|--13.91%--__bitmap_and
|--3.01%--pipapo_refill
|--0.81%--__kmalloc
| --0.74%--__kmalloc_large_node
| --0.66%--__alloc_pages
..
--0.52%--memset_orig
So lots of time is spent in copying exising elements to make space for
the next one.
Instead of allocating to the exact size of the new rule count, allocate
extra slack to reduce alloc/copy/free overhead.
After:
time nft -f pipapo_800k
real 1m54.110s
user 0m2.515s
sys 1m51.377s
--80.46%--nft_pipapo_insert
|--73.45%--pipapo_get.isra.0
|--57.63%--__bitmap_and
| |--8.52%--pipapo_refill
|--3.45%--__kmalloc
| --3.05%--__kmalloc_large_node
| --2.58%--__alloc_pages
--2.59%--memset_orig
|--6.51%--pipapo_insert
--5.96%--pipapo_resize
|--3.63%--memcpy_orig
--2.13%--kvmalloc_node
The new @rules_alloc fills a hole, so struct size doesn't go up.
Also make it so rule removal doesn't shrink unless the free/extra space
exceeds two pages. This should be safe as well:
When a rule gets removed, the attempt to lower the allocated size is
already allowed to fail.
Exception: do exact allocations as long as set is very small (less
than one page needed).
v2: address comments from Stefano:
kdoc comment
formatting changes
remove redundant assignment
switch back to PAGE_SIZE
Link: https://lore.kernel.org/netfilter-devel/20240213141753.17ef27a6@elisabeth/
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
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| fs | ||
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| init | ||
| io_uring | ||
| ipc | ||
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| lib | ||
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| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.